Reduced Defect Density in MOCVD-Grown MoS₂ by Manipulating the Precursor Phase

Abstract

Advancements in the synthesis of large-area, high-quality two-dimensional transition metal dichalcogenides such as MoS₂ play a crucial role in the development of future electronic and optoelectronic devices. The presence of defects formed by sulfur vacancies in MoS₂ results in low photoluminescence emission and imparts high n-type doping behavior, thus substantially affecting material quality. Herein, we report a new method in which single-phase (liquid) precursors are used for the metal-organic chemical vapor deposition (MOCVD) growth of a MoS₂ film. Furthermore, we fabricated a high-performance photodetector (PD) and achieved improved photoresponsivity and faster photoresponse in the spectral range 405-637 nm compared to those of PDs fabricated by the conventional MOCVD method. In addition, the fabricated MoS₂ thin film showed a threshold voltage shift in the positive gate bias direction owing to the reduced number of S vacancy defects in the MoS₂ lattice. Thus, our method significantly improved the synthesis of monolayer MoS₂ and can expand the application scope of high-quality, atomically thin materials in large-scale electronic and optoelectronic devices.